There should be a difference between deciding when to buy or sell and actually taking action on that decision. By using a longer time frame in making decisions about buying and selling, you minimize the chance of falling prey to the short term gyrations of stock prices. Once a decision is made in a longer time frame, then zoom in to a shorter time frame to actually time your action. An example for a longer term trader would be to use the weekly chart for deciding on the trend of a stock, and the daily chart for timing your entry/exit. Short term traders might use a 60-minute chart to assess the trend and decide that they want to participate, and then a 15- or 5-minute chart to take action on that decision. Using distinct time frames builds consistency and accuracy in your trading.